I have stayed at the Poly but was never on the 1st floor. We always had a garden view on the second floor (no balcony). It was nice. But... I am going in December of this year and find myself with the same question as you. I have heard that the 1st floor patio's are very nice indeed, and very convenient to step out to the beach. Will you have children with you? To me this would make a big difference. However, when we went with our young kids it did not seem like a deterrent to not be on the ground floor. Looking back, we were all just so excited to be there we did not even think of what floor to stay on!
I think I am going to stay with my original decision to stay on the 3rd floor for our Dec trip. We are empty nesters and I don't think that the beach will be that big of a draw in December. We are also opting for a LVC room this go round. It is our 25th wedding anniversary. What the heck!
Good luck with your decision. The Poly is a great resort no matter where you stay.